Prevalence
Primary shoulder dislocate peaks in the second and sixth decade
98% of cases, shoulder displaces anteriorly
2% of cases, shoulder displaces posteriorly
95% of first-time shoulder dislocations result from either a forceful collision, falling on an outstretched arm or a sudden wrenching movement
5% of dislocations have an atraumatic origin (minor incidents such as raising the arm or moving during sleep
70% of people who have dislocated can expect to dislocate again within 2 years of the initial injury
Younger and older subjects have a comparable incidence of primary shoulder dislocation
Incidence of recurrent dislocation is much more frequent in adolescent population
Dislocation reported to recur in:
66% to 100% of people aged 20 years or under
13% to 63% of people aged between 20 and 40 years old
0% to 16% of people aged 40 years or older